Showing papers on "Filter capacitor published in 2007"

Passive Filter Design for Three-Phase Inverter Interfacing in Distributed Generation

Abstract: With the growing use of inverters in distributed generation, the problem of injected harmonics becomes critical. These harmonics require the connection of low pass filters between the inverter and the network. This paper presents a design method for the output LC filter in grid coupled applications in distributed generation systems. The design is according to the harmonics standards that determine the level of current harmonics injected into the grid network. Analytical expressions for the maximum inductor ripple current are derived. The filter capacitor design depends on the allowable level of switching components injected into the grid. Different passive filter damping techniques to suppress resonance affects are investigated and evaluated. Simulated results are included to verify the derived expressions.

Switched capacitor converters

Abstract: A switched capacitor converter has a supply voltage input, an output circuit with one or more load capacitors, a semiconductor switch network. The switch network is connected at a switch junction point and across the voltage input, and has one or more pairs of said first and second switches. Each pair of switches is associated with one of the load capacitors and each pair is connected in series. The converter also has a charging capacitor network connected across the semiconductor switch network and across the voltage input. The charging capacitor network has one or more charging capacitors and inductances connected between the switch junction point and the output circuit. Each of the charging capacitors and inductances is associated with one of the load capacitors. The load capacitors are each charged by the associated charging capacitor when the associated first switch is closed and the associated second switch is open. And the load capacitors are each discharged by the associated inductance when the associated first switch is closed and the associated second switch is open.

A Single-Phase Grid-Connected Inverter with a Power Decoupling Function

Abstract: This paper presents a single-phase grid connected inverter with a power decoupling circuit. In the single-phase grid connected inverter, it is well known that a power pulsation with twice the grid frequency is contained in the input power. In a conventional inverter, electrolytic capacitors with large capacitance have been used in order to smooth the DC voltage. However, lifetime of those capacitors is shortened by the power pulsation with twice grid frequency. The authors have been studied a active power decoupling method that reduce the pulsating power on the input DC bus line, this enables to transfer the ripple energy appeared on the input DC capacitors into the energy in a small film capacitor on the additional circuit. Hence, extension of the lifetime of the inverter can be expected because the small film capacitor substitutes for the large electrolytic capacitors. Finally, simulation and experimental results are discussed.

EMI Suppression in Voltage Source Converters by Utilizing dc-link Decoupling Capacitors

Abstract: Direct current (dc)-link decoupling capacitors are normally used to control the voltage overshoot of switching devices in voltage source converters. This paper analyzes decoupling capacitors' impacts on device electromagnetic interference (EMI) noise as well as on device voltage stress. The design and selection of decoupling capacitors considering both voltage stress and EMI suppression are presented. A new high-frequency EMI filter by utilizing the decoupling capacitors is proposed. The filter is adopted as a local EMI filter for power modules. The integratable characteristics of the proposed filter are discussed. Simulation and experimental results verify the design. This high-frequency filter shows good attenuation for high-frequency EMI noise and voltage overshoot suppression.

Single-Phase SRM Drive With Torque Ripple Reduction and Power Factor Correction

Abstract: In a single-phase switched reluctance motor (SRM) drive, the dc voltage source is generally supplied by a circuit consisting of a bridge rectifier and a filter capacitor connected to an ac line. The charging time of the capacitor is shorter from the ac source as capacity increases. The bridge rectifier draws pulsating current from the ac source, which results in a degraded power factor (PF) and lower system efficiency. A single-phase SRM drive system is presented in this paper, which includes the realization of a drive circuit for the reduction of torque ripple and PF improvement with a novel switching topology. The proposed drive circuit adds one switch and one diode, which can separate the output of the ac/dc rectifier from the large capacitor and supply power to the SRM alternately. This allows the drive system to realize torque ripple reduction and PF improvement through the switching scheme. The validity of the proposed method is analyzed by mathematical modeling and tested by simulations and experiments.

Robust control scheme for a microgrid with PFC capacitor connected

Abstract: Capacitors are widely used for power-factor correction (PFC) in power systems. When a PFC capacitor is installed with a certain load in a microgrid, it may be in parallel with the filter capacitor of the inverter interfacing the utility grid and the local distributed-generation unit and, thus, change the effective filter capacitance. Another complication is the possibility of occurrence of resonance in the microgrid. This paper conducts an in-depth investigation of the effective shunt-filter-capacitance variation and resonance phenomena in a microgrid due to a connection of a PFC capacitor. To compensate the capacitance-parameter variation, an Hinfin controller is designed for the voltage-source- inverter voltage control. By properly choosing the weighting functions, the synthesized Hinfin controller would exhibit high gains at the vicinity of the line frequency, similar to traditional high- performance P+ resonant controller and, thus, would possess nearly zero steady-state error. However, with the robust Hinfin controller, it will be possible to explicitly specify the degree of robustness in face of parameter variations. Furthermore, a thorough investigation is carried out to study the performance of inner current-loop feedback variables under resonance conditions. It reveals that filter-inductor current feedback is more effective in damping the resonance. This resonance can be further attenuated by employing the dual-inverter microgrid conditioner and controlling the series inverter as a virtual resistor affecting only harmonic components without interference with the fundamental power flow. And finally, the study in this paper has been tested experimentally using an experimental microgrid prototype.

Measured CMOS Switched High-Quality Capacitors in a Reconfigurable Matching Network

Abstract: Switched capacitors are here investigated for use in reconfigurable matching networks, particularly for digital video broadcasting-handheld (DVB-H) frequencies. A 0.13-μm CMOS circuit is evaluated through both simulations and measurements. Source grounded nMOS transistors are used to switch high-quality metal capacitors located above metal layer 8. The quality factor and tuning range depend on frequency, switch voltage, capacitor size, and transistor width. There is a clear tradeoff between quality factor and tuning range, and measurements show quality factors above 50, 100, and 150 at tuning ranges of 3.9, 2.4, and 1.6, respectively. A reconfigurable matching network with the switched capacitors has been realized using external inductors and the measured matching domain for the DVB-H frequency band is shown. The total loss of the network is 1.0 dB, a result of the high-quality switched capacitors.

Control of grid connected AC-DC converters with minimized DC link capacitance under unbalanced grid voltage condition

Abstract: Due to the limited lifetime of electrolytic capacitors, use of film capacitors is gaining popularity in AC-DC converter applications. In order to constrain both cost and converter volume while using film capacitors, small DC link capacitance values must be employed. Two challenges are associated with converters that have small DC link capacitors. First, such converters are highly susceptible to transient over/under voltages on the DC link. Secondly, even minor grid voltage imbalance can cause large 2nd harmonic DC link voltage ripple to appear, possibly interfering with the load. This paper details a control scheme that overcomes both these problems. A feedforward matrix is employed to generate a set of reference current commands that are processed by high bandwidth stationary frame current controllers. A novel DC link voltage controller combines load feedforward with a resonant term to reduce transient over/under voltages and improve immunity to 2nd harmonic voltage ripple under unbalanced grid conditions. Experimental results demonstrate the efficacy of the proposed converter controller.

Design, Modeling, and Characterization of Embedded Capacitor Networks for Core Decoupling in the Package

Abstract: Embedded passives are gaining in importance due to the reduction in size of electronic products. Capacitors pose the biggest challenge for integration in packages due to the large capacitance required for decoupling high performance circuits. Surface mount discrete (SMD) capacitors become ineffective charge providers above 100 MHz due to the increased effect of loop inductance. This paper focuses on the importance of embedded capacitors above this frequency. Modeling, measurements, and model to hardware correlation of these capacitors are shown. Design and modeling of embedded capacitor arrays for decoupling processors in the midfrequency band (100 MHz-2 GHz) is also highlighted in this paper.

Thermal Leakage Improvement by Using a High-Work-Function Ni Electrode in High- κ TiHfO Metal–Insulator–Metal Capacitors

Abstract: An unavoidable drawback when using high-K dielectrics in capacitors is the small bandgap and the related reduction in the band-offset, which results in a large leakage current at elevated temperatures. We report improvements in the thermal leakage current by using Ni as a high-work-function top electrode for high-K TiHfO capacitors. This avoids sacrificing the overall K value by using a multilayer or laminate structure and results in better voltage linearity, which is important for analog/radio frequency integrated circuits.

Fuzzy Logic Controller Based Three-phase Shunt Active Filter for Line Harmonics Reduction

Abstract: Harmonic distortion is a form of electrical noise. It is a superposition of signals, which are of multiples of fundamental frequency. Proliferation of large power electronic systems results in increased harmonic distortion. Harmonic distortion results in reduction of power quality and system stability. This paper presents fuzzy control applicable for active power filter for three-phase systems, which are comprised of nonlinear loads. The active filter is based on a three-phase inverter with six controllable switches. The AC side of the inverter is connected in parallel with the other nonlinear loads through a filter inductance. The DC side of the inverter is connected to a filter capacitor. The Fuzzy Controller (FC) is used to shape the current through the filter inductor such that the line current is in phase with and of the same shape as the input voltage. The results of the computer simulation prove that the injected harmonics are greatly reduced, system efficiency and power factor are improved.

Efficient placement of distributed on-chip decoupling capacitors in nanoscale ICs

Abstract: Decoupling capacitors are widely used to reduce power supply noise. On-chip decoupling capacitors have traditionally been allocated into the white space available on the die based on an unsystematic or ad hoc approach. In this way, large decoupling capacitors are often placed at a significant distance from the current load, compromising the signal integrity of the system. This issue of power delivery cannot be alleviated by simply increasing the size of the on-chip decoupling capacitors. To be effective, the on-chip decoupling capacitors should be placed physically close to the current loads. The area occupied by the on-chip decoupling capacitor, however, is directly proportional to the magnitude of the capacitor. The minimum impedance between the on-chip decoupling capacitor and the current load is therefore fundamentally affected by the magnitude of the capacitor. A distributed on-chip decoupling capacitor network is proposed in this paper. A system of distributed on-chip decoupling capacitors is shown to provide an efficient solution for providing the required on-chip decoupling capacitance under existing technology constraints. In a system of distributed on-chip decoupling capacitors, each capacitor is sized based on the parasitic impedance of the power distribution grid. Various tradeoffs in a system of distributed on-chip decoupling capacitors are also discussed. Related simulation results for typical values of on-chip parasitic resistance are also presented. An analytic solution is shown to provide accurate distributed system. The worst case error is 0.003% as compared to SPICE. Techniques presented in this paper are applicable not only for current technologies, but also provide an efficient placement of the on-chip decoupling capacitors in future technology generations.

High voltage cable testing method

Abstract: A method of testing a cabling system is disclosed. The method may include discharging an input filter capacitor associated with an accessory component, charging an accessory bus capacitor to a desired voltage level, and connecting the accessory bus capacitor to the input filter capacitor. The method may also include continuously monitoring a voltage waveform associated with the accessory bus capacitor. The method may further include determining a difference between the voltage waveform and a nominal voltage profile, and detecting a fault if the difference is greater than a threshold value.

Implementation and Performance of an Anti-Resonance Hybrid Delta-Connected Capacitor Bank for Power Factor Correction

Abstract: This paper presents a new three-phase anti-resonance hybrid delta-connected capacitor bank for power factor correction in low-voltage industrial power systems. In general, shunt capacitors connected in series with reactors should be designed carefully before installation in order to avoid series and/or parallel harmonic resonance between the capacitors and system inductances. However, the system parameters vary dynamically according to the power system configurations and loads. Consequently, harmonic resonance might occur after the capacitors have been installed. The main objective of the proposed hybrid capacitor bank is to compensate for reactive power without any harmonic resonance. The hybrid capacitor bank is a combination of delta-connected capacitors connecting in series with three small-rating single-phase inverters without any matching transformer. The inverter is used to improve the characteristics of the capacitors. This paper deals with the implementation and control of the hybrid capacitor bank. Experimental results verify the viability and the effectiveness of the proposed anti-resonance hybrid delta-connected capacitor bank for reactive power compensation.

Micro-electromechanical voltage tunable capacitor and and filter devices

Abstract: Disclosed are one-port and two-port voltage-tunable micro-electromechanical capacitors, switches, and filter devices. High aspect-ratio metal micromachining is used to implement very high quality factor (Q) tunable and fixed capacitors, fixed inductors, and low insertion loss tunable and fixed bandpass LC filters. The tunable capacitors can move in the plane of the substrate by the application of DC voltages and achieve greater than 100% of tuning. A combination of low-loss substrate and highest conductivity metal is used to achieve record high Q and low insertion loss at radio frequencies. The disclosed tunable capacitor structure can also be used as a micromechanical switch.

Phase shifted H-Bridge resonant converter with symmetrical currents

Abstract: A phase shifted H-bridge resonant converter with symmetrical currents includes, a DC storage cap ( 31 ), four switches ( 1 - 4 ) with a parallel turn off network consisting of diodes ( 5 - 8 ), capacitors ( 9 ), ( 11 ), ( 14 ), ( 16 ), resistors ( 10 ), ( 12 ), ( 13 ), ( 15 ). The subsequent output of switches ( 1 - 4 ), is arranged in series with DC blocking caps ( 17 - 18 ), connected to a low mutually coupled inductor ( 32 ), an AC resistive load, capacitor ( 19 ), resistor ( 20 ) across inductor ( 32 ), with capacitors ( 22 ), ( 23 ) that comprise a resonant tank circuit, and is connected to the primary of transformer (21) wherein the interaction between the two coils of the low mutually coupled inductor ( 32 ) provides symmetrical currents within the switches and resonant tank circuit. Further, output rectification may be arranged by use of secondary winding of transformer ( 21 ), diodes ( 24 - 27 ), filter inductor ( 28 ), filter capacitor ( 29 ), and load resistor ( 30 ).

Isolated Boost Converters

Abstract: Two implementations of the isolated boost converter that exhibit no parasitic voltage ringing across all semiconductor devices on the primary and secondary sides of the transformer are introduced Ringing-free operation is achieved by clamping the voltages of the primary switches and rectifiers to the voltage of the primary-side energy-storage capacitor and clamping the voltage across the secondary-side rectifiers to the output filter capacitor The performance of the proposed topology was verified on a dual ac-input, 900-W experimental prototype operating at 67 kHz

Lifetime of Film Capacitors in Single-Phase Regenerative Induction Motor Drives

Abstract: Metallized polypropylene film capacitors (MPPF) are a very interesting alternative to electrolytic capacitors, because they can withstand much higher levels of surge voltage, very high RMS currents, and offer longer lifetimes. This paper analyses the lifetime of MPPF capacitors present in the DC link of a single-phase regenerative induction motor (IM) drive. The system under analysis contains a single-phase active rectifier in the front end, a MPPF capacitor in the DC link, and an inverter which supplies a three-phase induction motor with indirect rotor field oriented control (IRFOC). The results are based on simulations and evaluations obtained through Matlab/Simulink combined with lifetime model from a film capacitor manufacturer.

Capacitive loads by a voltage-source active filter

Abstract: Usually the filter current of an active filter (VSI-type) is controlled by a two-step controller and the disturbance (load current) is added to the control circuit. This method becomes unstable, if capacitive loads have to be compensated. It is shown in this paper, that the algorithm can be stabilized by additional filter capacitors. So the control circuit remains stable also at the compensation of capacitive loads.

Noise filter array

Abstract: A noise filter array includes filter elements, each of which includes an LC parallel resonant circuit having a coil and a capacitor and an LC series resonant circuit having a coil and a capacitor, are arranged substantially parallel to one another in an array and integrally provided. Grounding capacitors that define the filter elements are arranged so that a common ground-side electrode faces signal-side electrodes and is connected to an inductance adjusting conductor that defines the LC series resonant circuits along with the capacitors through a via hole. The lengths of the inductance adjusting conductor from a connection location within the via hole to ground terminals are substantially equal in each of the filter elements.

Three-level double step-down full bridge inverter

Abstract: The invention relates to a five-potential dual-reduction full-bridge inverter, wherein it comprises power circuit (1), two reduction circuits (2, 3) whose inputs are connected to power circuit (1) and outputs are connected to filter capacitor and load circuit (4), work-frequency switch circuit (5) connected to all circuits The switch tubes (Q51, Q52) are reversely connected into bidirectional baffle switch (S5); the source of filter capacitor (Cf) via added switch tubes (S3, S4, S5) are connected to the anode, cathode and middle point of direct-current bus voltage; the external bus voltage is reduced from +-Ud to +-Ud/2 The invention has simple structure and low harmonic component, etc

Power factor correction power supply

Abstract: Provided herein is a power factor correction (PFC) power supply, comprising: a bridge rectifier having an input and an output, a filter capacitor connected to the output of the bridge rectifier, a transformer having a primary winding, a fly-back winding and a secondary winding, a forward diode, a fly-back diode, a storage capacitor circuit having a valley-fill circuit and a capacitor connected in parallel, and a switch connected between the primary winding and the output of the bridge rectifier. The PFC power supply features improved efficiency and low switching loss.

Current measuring arrangement of a frequency converter

Abstract: Method and appliance for measuring the output current of a frequency converter, which frequency converter contains a network bridge (10) that can be connected to an AC network, a controllable three-phase load bridge (11) that can be connected to an AC load, and a DC intermediate circuit between them, which contains a filter capacitor, which load bridge contains controllable semiconductor switches in each phase, which are controlled by pulse-width modulation, and in which the currents of the output phases are determined by means of measured samples of the current of the filter capacitor of the DC intermediate circuit.

Investigation of Bifurcation and Chaos in Forward Converter

Abstract: This paper concentrate on the numerical study and simulation experiment of bifurcation and chaos in the forward converter, which is different from the previous investigated work in DC-DC converter without power transformer. First, the simplified model of transformer is built. Then, the iterative map for forward converter is derived. Based on the model, this paper provides the stable condition. According to the stable condition, we change the parameters of circuit, such as filter capacitor, filter inductance and load resistance, and investigate the bifurcation and chaos of forward converter including the time-domain waveforms, v-i phase portraits. There is good agreement between theory and experiment.

Two-way AC chopper

Abstract: The invention relates to a bidirectional alternative-current chopper, which comprises the first and second buck (boost) circuit, wherein in the first buck(boost) circuit, the cathode of first switch and the anode of second switch are connected, while the connecting point is connected to one end of first inductance filter; in the second buck(boost) circuit, the anode of third switch is connected to the cathode of fourth switch, while the connecting point is connected to one end of second inductance filter; another end of first inductance filter and another end of second inductance filter are connected to one end of second inductance capacitor; the anode of first switch and the cathode of third switch are connected to one end of first filter capacitor; the cathode of second switch, the anode of fourth switch, another end of first filter capacitor, and another end of second filter capacitor are connected. The invention can avoid control dead area, to solve current diversion.

Automatic power source configuration

Abstract: A circuit to supply power to a detachable load incorporates a power source, a power converter and an array of capacitors. Upon connection of the detachable load, the capacitors of the array of capacitors are automatically configured into a desired series, parallel or combination series and parallel configuration of interconnections to accommodate limitations in the voltage ranges of the capacitors in being coupled to the load and/or to achieve other desired characteristics of electrical power to be provided to the load. Further, upon connection of the detachable load, a limit on current flow imposed by the power converter may be set to a desired level to achieve desired characteristics of electrical power to be provided to the load and/or desired characteristics of charging and discharging behaviors of the array of capacitors.

Circuit arrangement and method for increasing the safety of an electronic operating device

Abstract: The invention relates to a circuit arrangement and to a method for increasing the safety of an electronic operating device, comprising power input terminals (3), a power input filter (1) having X capacitors (XC1, XC2), a rectifier part (2) having filter capacitors (C1), and a dc converter (4), wherein upon the disconnection of the supply voltage a consumer is switched on for a defined period of time, and the consumer and the time period are selected such that the residual energy stored in the capacitors (XC1, XC2, C1) is consumed, and thereby within a very short time the voltage at the power input terminals (3) is reduced to a value that is not harmful to people.

Symmetric Vertical Parallel Plate Capacitors for On-Chip RF Circuits in 65-nm SOI Technology

Abstract: This letter presents symmetric vertical parallel plate (VPP) capacitors in 65-nm silicon-on-insulator CMOS technology. Three VPP capacitors with different metal layer options are examined with respect to effective capacitance density and -factor. An effective capacitance of 2.18 and a -factor of 23.2 at 1 GHz are obtained from a 1x + 2x (M1-M6) metal layer configuration's pre-de-embedding measurement. VPP capacitor symmetry, mismatch, leakage current density, vertical scalability, and variation characteristics from a 300-mm wafer are discussed.

High pass filter with above IC integrated SrTiO3 high K MIM capacitors

Abstract: This paper describes realization and characterization of SrTiO 3 (STO) high K MIM capacitors above BiCMOS integrated circuit (IC). These capacitances are connected to IC and are used as coupling capacitors in order to realize a high pass filter. Surface capacitance achieved is 10 nF/mm 2 with capacitance value of 1.2 nF. The process for STO MIM fabrication does not exceed 400 °C, which is compatible with interconnections. Typical K and dielectric losses values obtained are, respectively 110% and 2%. Yield obtained reaches 83% for capacitors. A functional high pass filter using these STO capacitors was realized in this study. It exhibits a cut-off frequency at 6.5 kHz and a constant gain at higher frequencies of −1.3 dB.

Plate Orientation Effect on the Inductance of Multi-Layer Ceramic Capacitors

Abstract: Various multi-layer ceramic capacitor (MLCC) geometries with horizontally and vertically oriented plates are modeled to determine the equivalent series inductance. It shows that the plate stack location and dimensions (independent of plate orientation) are the most significant factors affecting the inductance.